1. Field of the Invention
The present invention relates to an XYZ-axes table, and more particularly to an XYZ-axes table used for positioning a mask in a stepper device for producing a semiconductor, a machine tool and the other exposure apparatus.
2. Description of the Prior Art
In a conventional XYZ-axes table, in the case of using a linear motor, a linear motor having a structure in which a rotary machine is cut and opened so as to be driven in a linear manner.
In the XYZ-axes table, since the linear motor described in the prior art has a lot of leakage flux between an armature and a movable element, and a magnetic attraction force is applied to a portion between the armature and the movable element in one direction, a great load is applied to a support mechanism of the movable element, so that there is a problem that a strain is generated in the structure.
An object of the present invention is to provide an XYZ-axes table in which a magnetic attraction force generated between the armature and the movable element is made small by reducing a leakage of a magnetic flux passing through a portion between the armature and the movable element.
In accordance with one aspect of the present invention, there is provided an XYZ-axes table provided with a base, a plurality of linear guiding apparatuses, a stage, an X-axis drive linear motor, a Y-axis drive linear motor and a Z-axis drive linear motor. It is desirable that the linear motor is structured such as to be constituted by an armature and a movable element being capable of relatively moving with respect to the armature. Further, it is desirable that the structure is made such that the linear motor further has one magnetic pole teeth rows which are magnetically connected to one magnetic pole of the armature and are arranged so as to be separated into a first stage and a second stage in a substantially vertical direction to a moving direction of the movable element, and another magnetic pole teeth rows which are magnetically connected to another magnetic pole of the movable element and are arranged so as to be separated into a first stage and a second stage in a substantially vertical direction to the moving direction of the movable element, the first stage of magnetic pole teeth in the one magnetic pole teeth rows and the first stage of magnetic pole teeth in the another magnetic pole teeth row are alternately arranged with respect to the moving direction of the movable element, the second stage of magnetic pole teeth in the one magnetic pole teeth rows and the second stage of magnetic pole teeth in the another magnetic pole teeth row are alternately arranged with respect to the moving direction of the movable element, and the movable element is arranged between the one and another first stage of magnetic pole teeth rows and the one and another second stage of magnetic pole teeth rows.
In accordance with another aspect of the present invention, there is provided an XYZ-axes table structured such that the rails of the linear guiding apparatus are arranged at four portions comprising east, west, south and north portions of the base, the rails are integrally formed so that the slider guided by the rail so as to be freely moves and a relative moving direction of the armature form a vertical angle, the movable element is connected to the stage so as to form a cross shape, and the armature arranged in one east-west direction and the movable element arranged in another south-north direction are respectively driven as an X-axis drive linear motor and a Y-axis drive linear motor.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that four rails of the linear guiding apparatus are arranged in four portions comprising west, east, south and north portions on the base, the movable elements are overlapped and arranged with keeping a gap so as to form a cross shape, the sliders guided by the rails so as to freely move are connected to both ends thereof so that relative moving directions between the sliders and the movable elements are vertical with each other, the plurality of armatures are integrally formed with the stage by being gathered to an inner side of the linear guiding apparatus, the armature arranged in one east-west direction and the armature arranged in another south-north direction are respectively driven as the X-axis drive linear motor and the Y-axis drive linear motor.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that the rails of the linear guiding apparatus are arranged in the base so that the X and Y axes vertically cross to each other, the sliders guided by the rails so as to freely move are integrally formed with the armatures so that relative moving directions are vertical, the armatures are connected to the stage so as to form an L shape, and the armature arranged in one east-west direction and the armature arranged in another south-north direction are respectively driven as the X-axis drive linear motor and the Y-axis drive linear motor.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that an XY table and a Z-axis linear guiding apparatus respectively have a function of driving at an angle xcex8.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that each of the linear guiding apparatuses is independently arranged on the base or one-axis linear guiding apparatus is overlaid on another-axis linear apparatus, whereby the linear motor is used.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table, further comprising a closed loop control system constituted by the linear motor, a sensor detecting a relative displacement between the armature and the movable element and a magnetic pole, a control portion feeding back a signal of the sensor, and a power drive portion.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table, further comprising an open loop control system constituted by the linear motor, a control portion and a power drive portion.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table, further comprising a control system constituted by the linear motor, a power drive portion, and a control portion including estimating means for detecting an induced voltage of the linear motor and estimating a relative magnetic pole position between the armature and the movable element on the basis of the voltage detected value.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table, further comprising a control system comprising a linear motor, a power drive portion, and a control portion including estimating means for detecting an electric current flowing through the linear motor and estimating a relative magnetic pole position between the armature and the movable element on the basis of the current detected value.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that a plurality of armatures of the coaxially-driven linear motor are arranged and a pitch between magnetic pole teeth of the adjacent different armatures is set to (kxc2x7P+P/M){(k=0, 1, 2, . . . ), (M=2, 3, 4, . . . )}{in which k is a number freely selected in a range that the adjacent armatures can be arranged, M is a number of phase of the motor} when the pole pitch is set to P.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that a through hole is provided in center portions of both of the XY table and the base.
In accordance with the other aspect of the present invention, there is provided an XYZ-axes table structured such that a compression air floating function or a magnetic floating function is provided between the base and the stage.
In accordance with the other aspect of the present invention, there is provided a semiconductor producing stepper apparatus, a machine tool or an exposing apparatus having the XY table or the XYZ-axes table as recited in any one of the previous features.
The features mentioned above and the other features of the present invention will be described below.